KR20150041755A - Method for forming ti-containing film by peald using tdmat or tdeat - Google Patents

Abstract

A method for forming a Ti-containing film on a substrate by plasma enhanced atom layer deposition (PEALD) by using tetrakise (dimethyl amino) titamium (TDMAT) or tetrakise (diethyl amino) titanium (TDEAT) comprises the steps of: applying TDMAT and/or TDEAT to a reaction space in which a substrate is arranged by pulse; continuously applying NH_3-free reaction gas to the reaction space; applying RF power to the reaction space by pulse, wherein the pulse of TDMAT and/or TDEAT and pulse of RF power is not overlapped, and repeating the steps for forming Ti-containing film on the substrate.

Description

METHOD FOR FORMING TI-CONTAINING FILM BY PEALD USING TDMAT OR TDEAT USING TDMAT,

The present invention generally relates to a method for forming a Ti containing film by plasma enhanced atomic layer deposition (PEALD) using tetrakis (dimethylamino) titanium (TDMAT) and / or tetrakis (diethylamino) titanium .

Ti based films have been formed for a long time by a sputtering method, a PVD method, and a CVD method. For example, TiN films having low sheet resistance have been used commercially as copper diffusion barrier films. Also, with the recent shrinkage of device nodes, spacer-defined double patterning (SDDP) has gradually begun to be used as a technology for miniaturization, and TiO and TiN are considered good candidates for hard masks for SDDP. For SDDP hard masks, conformal films with good step coverage are needed in terms of the nature of the hard masks, and therefore those skilled in the art will appreciate that TiO2 and TiN < RTI ID = 0.0 > Conformal membranes were used and evaluated. In particular, TiN is generally difficult to control stresses and it is likely to be strongly compressible, and thus controlling stress is one of the challenges. In addition, due to the miniaturization of device nodes, it has been difficult to form conformal films with good step coverage by conventional methods such as sputtering methods, PVD methods, and CVD methods, and therefore, as an alternative method, And a method of forming films having low sheet resistance are desired.

Summary of the Invention

According to some embodiments of the present invention, in using tetrakis (dimethylamino) titanium (TDMAT) or tetrakis (diethylamino) titanium (TDEAT) as a precursor for plasma enhanced atomic layer deposition (PEALD) By simply changing the reagent gas, various types of films can be formed, such as TiN, TiCN, TiO, TiON, and TiOCN films, and also the film quality of each film typical of the film can be controlled. In some embodiments, the reaction between the precursor and the ammonia used with the precursor may be avoided, although ammonia is not used at the same time as TDMAT or TDEAT, so that TDMAT or TDEAT is highly reactive with ammonia.

Among the various types of films, TiN films and thermally annealed TiO films may be constituted by crystalline components. The TiCN films may be composed of a mixture of crystalline and amorphous components, and if the carbon content of the TiCN films is high, the films are generally constituted by amorphous components. Other types of membranes are composed of amorphous components. In forming TiN and TiCN films, a nitrogen feed gas is often used for nitridation. However, in some embodiments, in forming TiN films, ammonia, which is a nitrogen feed gas, is not used but hydrogen is used as a reactant gas, thereby forming TiN films using nitrogen contained in the precursor itself . In some embodiments, only hydrogen gas is used as the reactant gas to form TiN films. In some embodiments, nitrogen gas may be used; Nitrogen gas is not used essentially as a nitrogen feed gas, but is used to control carbon concentration, film stress, and / or sheet resistance. Thus, some embodiments can be formed using TiN films using precursors that are methylamine species with nitrogen-titanium bonds, and by combining hydrogen flow, nitrogen flow, and / or RF power with other film- And the film quality can be effectively controlled.

 Any discussion of the problems and solutions associated with the related art is only included for purposes of providing a context for the present invention and acknowledged that some or all of the discussion was known at the time the invention was made It should not be imported.

For purposes of summarizing the aspects of the invention and the advantages achieved relative to the related art, certain objects and advantages of the invention are set forth in the present disclosure. Of course, it should be understood that not all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will readily appreciate that the present invention is not limited to achieving other objects or advantages, such as may be taught or suggested herein, but rather achieves one or a group of benefits or advantages as taught herein Or may be embodied or performed in a manner that is optimized.

 Further aspects, features and advantages of the present invention will become apparent from the following detailed description.

These and other aspects of the present invention will now be described with reference to the drawings of preferred embodiments, which are intended to illustrate the invention without limiting the invention. The figures are greatly simplified for illustrative purposes and are not necessarily to scale.
1 is a schematic view of a PEALD device for forming a dielectric film usable in an embodiment of the present invention.
Figure 2 (a) shows the chemical formula of tetrakis (dimethylamino) titanium (TDMAT).
Fig. 2 (b) is a schematic illustration showing a matrix structure of a crystalline TiN film formed using a hydrogen plasma according to an embodiment of the present invention, where the NC bonds are broken, and the carbons do not enter the matrix.
Figure 2 (c) is a schematic illustration showing a matrix structure of an amorphous TiCN film formed without the use of a hydrogen plasma, where the NC bonds are retained and the carbons enter the matrix and interfere with the formation of a crystalline structure.
Figure 3 shows the results of an X-ray diffraction analysis of an annealed film, showing that the film forms anatase type crystals, in accordance with an embodiment of the present invention.
4 is a transmission electron microscope (TEM) photograph of a cross-sectional view of a conformal TiCN film according to an embodiment of the present invention.
Figure 5 depicts the process steps of the PEALD method for depositing a dielectric film using ammonia as a reactant gas in accordance with an embodiment of the present invention.
Figure 6 depicts the process steps of the PEALD method for depositing a dielectric film in accordance with some embodiments of the present invention.
7 is a schematic view showing a laminate structure of a TiON or TiOCN film composed of TiN and TiO films or TiCN and TiO films according to an embodiment of the present invention.
8 is a graph showing dry etch rates of a TiN film, a TiO film, and a TiON film in accordance with some embodiments of the present invention.
9 is a graph showing wet etch rates of a TiN film, a TiO 2 film, and a TiON film in accordance with some embodiments of the present invention.
Figure 10 shows Fourier Transform Infrared (FT-IR) spectra of TiCN films according to some embodiments of the present invention.
Figure 11 shows Fourier Transform Infrared (FT-IR) spectra of TiCN films according to some embodiments of the present invention.
Figure 12 is a graph showing the range of film stresses related to the crystallinity of a TiN / TiCN film in accordance with some embodiments of the present invention.
Figure 13 shows Fourier Transform Infrared (FT-IR) spectra of TiCN films according to some embodiments of the present invention.
Figure 14 shows the results of X-ray diffraction analysis of (a) a TiCN film (carbon content: 6%) according to some embodiments of the present invention and (b) Ray diffraction analysis.
Figure 15 shows the results of (a) Fourier transform infrared (FT-IR) spectra of TiCN films and (b) X-ray diffraction analysis of TiCN films according to some embodiments of the present invention.
Figure 16 shows the results of (a) Fourier transform infrared (FT-IR) spectra of TiCN films and (b) X-ray diffraction (XRD) analysis of TiCN films according to some embodiments of the present invention.
Figure 17 shows a graph showing the relationship between membrane stress and hydrogen flow and a graph showing the relationship between membrane stress and RF power, in accordance with some embodiments of the present invention.

In the present disclosure, " gas " may comprise vaporized solids and / or liquid and may be constituted by a single gas or a mixture of gases. Similarly, the articles "a" or "an" refer to a species or to a genus comprising a plurality of species. In the present disclosure, the process gas, such as precursor gas and reactant gas, is introduced into the reaction chamber through the showerhead and may consist, consist essentially of, or consist of an active gas and an inert gas. That is, in the present disclosure, the "precursor gas" may be introduced with a carrier gas such as rare gas, and similarly, the "reactant gas" may be introduced with a carrier gas such as rare gas. Alternatively, the precursor or reagent gas may consist of an active gas. The rare gas may be introduced intermittently or continuously through the showerhead as purge gas. A gas other than the process gas, that is, the gas introduced without passing through the showerhead, may be used, for example, to seal the reaction space, which includes a seal gas such as rare gas. In some embodiments, a "film" is a layer that extends continuously in a direction perpendicular to the direction of thickness without substantially pinholes to form a layer covering the entire target or an associated surface, or simply a layer covering the target or associated surface Quot; In some embodiments, a "layer" refers to a structure or film synonym having a specific thickness formed on a surface. The film or layer may be composed of a discrete single film or layer with a specific property or multiple films or layers and the boundary between adjacent films or layers may be clear or otherwise And may be established based on physical, chemical and / or any other characteristics, forming processes or sequences, and / or functions or purposes of adjacent layers or layers. Also, in this disclosure, any two numbers of variables can constitute a workable range of a variable, since its operable range can be determined based on routine work, May include or exclude endpoints. In addition, any values of the indicated variables (whether indicated as "about" or not) may refer to exact or approximate values and may include equivalents, and in some embodiments , Mean, median, representative, majority, and the like.

Where conditions and / or structures are not specified in the present disclosure, those skilled in the art can readily provide such conditions and / or structures in view of this disclosure, as a matter of routine experimentation.

In any of the disclosed embodiments, any element used in the embodiments may be replaced by any element equivalent thereto and includes those explicitly, necessarily, or implicitly disclosed herein for intended purposes . Furthermore, the present invention is equally applicable to apparatus and methods.

In this disclosure, any defined meanings are not necessarily excluded from the ordinary and customary meanings in some embodiments.

In some embodiments, a method of forming a Ti-containing film on a substrate by plasma enhanced atomic layer deposition (PEALD) using tetrakis (dimethylamino) titanium (TDMAT) or tetrakis (diethylamino) (I) introducing TDMAT and / or TDEAT into the reaction space in which the substrate is placed in a pulse; (ii) continuously introducing an NH ₃ -containing reactant gas into the reaction space; (iii) applying RF power in pulses to the reaction space, wherein pulses of TDMAT and / or TDEAT and pulses of RF power do not overlap; And (iv) repeating steps (i) to (iii) to form a Ti-containing film on the substrate.

In some embodiments, TDMAT and TDEAT may include equivalent derivatives to these, where methyl groups and ethyl groups may be used interchangeably.

Above, "continuously" refers to without vacuum break, without interruption as a timeline, without changing processing conditions, or in some embodiments immediately thereafter.

In some embodiments, the NH ₃ -containing reactant gas is H ₂ and / or N ₂ . In some embodiments, the NH ₃ -containing reactant gas does not contain any of nitrogen, oxygen, and carbon. In some embodiments, the NH ₃ -containing reactant gas comprises H ₂ and rare gases (eg, He, Ar), thereby forming a TiN crystalline film as the Ti containing film in step (iv). Alternatively, in some embodiments, the NH ₃ -containing reactant gas comprises H ₂ , N ₂ , and rare gases (eg, He, Ar), thereby forming TiCN An amorphous film is formed. Alternatively, in some embodiments, the NH ₃ -containing reactant gas comprises oxygen, thereby forming a TiO 2 film as the Ti containing film in step (iv). In some embodiments, the method further comprises annealing the Ti-containing film on the substrate in an atmosphere of oxygen after step (iv) to form a TiO film having anatase crystal as the Ti containing film in step (iv) Where the amorphous TiO 2 is converted to anatase crystals. TiO 2 films with anatase crystals exhibit photocatalytic activity. After annealing, the surface of the TiO film acquires hydrophilicity, which is superhydrophilic inherent to the TiO 2 photocatalyst.

In some embodiments, the NH ₃ -containing reactant gas is comprised of a reactant gas that does not contain oxygen and a reactant gas that contains oxygen, and in step (iv), when steps (i) to (iii) The NH ₃ -free oxygen-free reagent gas and the NH ₃ -free oxygen-containing gas are alternately used at the set intervals. For example, the NH ₃ -free oxygen-free reactant gas is hydrogen gas without nitrogen gas, and the NH ₃ -free oxygen-containing gas is oxygen gas, whereby TiO 2 films composed of alternately deposited TiO 2 and TiN films Thereby forming a film. Alternatively, in some embodiments, the NH ₃ -free oxygen-free reagent gas is a hydrogen gas and a nitrogen gas, the NH ₃ -free oxygen containing gas is an oxygen gas, and the TiO 2 films And a TiCN film is formed. 7 is a view showing a TiON or TiOCN film 79 composed of TiN and TiCN films 72, 74, 76, and 78 and TiO films 73, 75, and 77 formed on a substrate 71 according to an embodiment of the present invention. Is a schematic view showing a laminate structure. In this embodiment, first, a cycle of forming a TiN or TiCN sublayer is performed 5 to 100 times to form a TiN or TiCN film 72 on the substrate 71, and then a cycle for forming a TiO sublayer Is performed once to form the TiO film 73 on the TiN or TiCN film 72. Similarly, a TiN or TiCN film 74, a TiO film 75, a TiN or TiCN film 76, a TiO film 77, and a TiN or TiCN film 78 are deposited in this order to form a laminate 79 do. In some embodiments, the number of cycles to form the TiO 2 film is significantly less than the number of cycles that form the TiN or TiCN film, i.e. the thickness of the TiO 2 film is significantly less than the thickness of the TiN or TiCN film. In some embodiments, the laminates (each laminate is comprised of a single TiN / TiCN film, which may consist of one or more TiN / TiCN sublayers, and a single TiO film, which may be comprised of one or more TiO sublayers) The number is about 3 to 200, typically 5 to 100. In some embodiments, the ratio of the number of cycles forming the TiO 2 film to the number of cycles forming the TiN / TiCN film in one laminate is from 1: 1 to 1: 200, typically from 1: 3 to 1: 100, May be from 1: 5 to 1:25. Figure 5 also shows the process steps of the PEALD method for depositing a dielectric film using ammonia as the reactant gas. Figure 6 depicts the process steps of the PEALD method for depositing a dielectric film in accordance with some embodiments of the present invention. In the embodiments illustrated in Figure 6, because ammonia is not used as the reactant gas, the reactant gases (nitrogen, hydrogen, and / or oxygen) can be continuously supplied and the pulses of the precursor feed and the RF power It can function as a purge gas between pulses. Above, the reactant gas is supplied with a rare gas (not shown) used as a carrier gas. In contrast, in Figure 5, because ammonia was used as the reactant gas, the reactant gases must be supplied in pulses that are different from the pulses of the precursor feed, which should not overlap with each other and require a more complex control system.

In the present disclosure, the TiN, TiON, TiCN, TiOCN, TiO2 films, and other Ti containing films are formed from a mixture of impurities, non-substantial elements such as hydrogen, Refers to films that do not exclude elements, or to films that are characterized primarily by the elements they represent, to films that are represented by the elements shown, or to those skilled in the art.

In some embodiments, a TiN film can be formed under the conditions shown in Table 1 below. Since ALD is a self-limiting adsorption reaction process, the amount of precursor molecules deposited is determined by the number of reactive surface sites, independent of the precursor exposure after saturation, and the supply of precursors thereby causing the reaction surface sites to saturate per cycle.

In some embodiments, a TiCN film can be formed under the conditions shown in Table 2 below.

In some embodiments, the TiON film may be formed under the conditions shown in Table 4 below.

In some embodiments, a TiOCN film can be formed under the conditions shown in Table 5 below.

In some embodiments, the thickness of the Ti containing film may range from about 0.3 nm to about 60 nm, typically from about 0.06 nm to about 300 nm, depending on the composition of the film, the intended use of the film, and the like.

In some embodiments, the TiO 2 film is annealed to form anatase crystals under the conditions shown in Table 6 below.

By performing the annealing, anatase type crystals, rutile-type crystals, or brookite-type type crystals can be formed, depending on the annealing temperature. For example, when the film is annealed at about 600 < 0 > C, anatase type crystals are formed. For annealing, any gas may be used as long as it provides an oxidizing atmosphere.

In some embodiments, the Ti containing film has a film stress of -2,500 MPa to 800 MPa. Figure 12 is a graph showing the range of film stresses related to the crystallinity of a TiN / TiCN film in accordance with some embodiments of the present invention. As shown in FIG. 12, when the film is very crystalline, that is, when it has a low carbon content, the film has a high compressive stress, and when the film is amorphous as a whole, the film has a compressive stress of about -400 MPa. When the carbon content of the film is between about 4% and about 9%, the film may have tensile stress, depending on the types of crystal structure contained in the film. That is, the film stress appears to be related to two or more types of crystal structures, and depending on the proportion of the crystal structures, the film exhibits high to low film stresses. However, when the carbon content of the film is less than about 4% or greater than about 9%, it appears that it is difficult to form crystalline structures exhibiting tensile stress. In some embodiments, when the carbon content of the film is about 6%, the film has a peak tensile stress, about 800 MPa. The minimum compressive stress of the film may be about -2,500 MPa or less, and when the carbon content of the film is not detectable (ND), the film may exhibit the lowest compressive stress. When the carbon content of the film is greater than about 6%, the film may not exhibit the lowest compressive stress.

The crystalline quality of the film can be adjusted by changing film formation parameters. In some embodiments, the method comprises: (a) determining a reference flow rate of H ₂ used as the reactant gas in step (ii), a reference RF power used in step (iii), and (i) (iii) setting a target film stress for the Ti-containing film that is greater than the film stress of the TiN crystalline film deposited by the steps (i) to (iv) under film-forming conditions comprising the reference film-forming temperature throughout; And (b) setting a film forming temperature throughout the steps (i) to (iii), wherein the flow rate of H ₂ used as the reactant gas in step (ii), the RF power used in step (iii) ₂ is used as a control parameter for changing the film stress and only one of at least one of the flow rate, the RF power and the film forming temperature is different from the reference flow rate of H ₂ , the reference RF power, and the reference film forming temperature, (I) to (iv) in order to form a film containing a silicon-containing film. In general, the higher the RF power, the lower the membrane stress, the higher the temperature, the higher the membrane stress, the higher the hydrogen content, the higher the membrane stress. By referring to the reference values of the control parameters and adjusting the control parameters, the Ti containing film can be configured to have tensile film stress. For example, in order to provide a tensile film stress, the flow rate of H ₂ is may be set lower than the reference flow rate of the H ₂ being used for the TiN crystalline film, the RF power is more than the reference RF power used for TiN crystalline film And / or the film formation temperature may be set to be higher than the reference film formation temperature used in the TiN crystalline film. In some embodiments, when the Ti containing film contains about 4% to about 9% carbon, the film has tensile film stress.

The film stress depends on the bonding state in the film. In some embodiments, the Ti containing film exhibits peaks at 2,000 cm ^-1 and 1,400 cm ^-1 in a Fourier transform infrared spectroscopy (FT-IR) graph. Generally, peaks at 2,000 cm ^-1 exhibit tensile stresses, while peaks at 1,400 cm ^-1 exhibit compressive stresses. The sum of these stresses represents the stress of the film. Without peaks at 2,000 cm ^-1 and 1,400 cm ^-1 , the film exhibits strong compressive stresses, indicating that the film is constituted by TiN crystals. When the flow of the hydrogen gas used as the reactant gas is increased, first, the peak at 1,400 cm ^-1 disappears, and the film becomes a film having a tensile stress. In this state, when the RF power is increased, the peak at 2,000 cm <" ¹ > disappears indicating that the crystalline quality of the film increases and the film becomes a film with strong compressive stress. Thus, by adjusting the two parameters (hydrogen gas flow and RF power), the peaks in the FT-IR graph can be adjusted; That is, the film stress can be controlled. It is not known which bond corresponds to each peak, but when one of the peaks at 2,000 cm ^-1 and 1,400 cm ^-1 is reduced, the peaks are related to carbon because the carbon content in the film is reduced It is expected. In some embodiments, based on the height of the peak at 1400 cm < ^-1 > in the FT-IR graph, the relationship between hydrogen flow and membrane stress can be determined. The peak at 1,400 cm ^-1 by manipulating the hydrogen flow, and RF power can be lost more readily than the peak at 2,000 cm ^-1. In some embodiments, the peak at 2,000 cm ^-1 may be controlled by the temperature for film formation. When the temperature is high, the peak at 2,000 cm ^-1 becomes high.

In some embodiments, by increasing the hydrogen as the reactant gas, the peak at 1400 cm <" ¹ > is lowered and only the peak at 2000 cm < ^-1 > is maintained, thereby rendering the resulting film tensile. In this situation, by increasing the RF power, the peak at 2,000 cm <" ¹ > also disappeared, thereby making the resulting film compressible, and the film constituted by TiN crystals. When RF power is increased without using a hydrogen gas flow, the peak at 1,400 cm <" ¹ > is higher and the membrane stress becomes very compressive. In some embodiments, the peak at 1,400 cm ^-1 corresponds to the number of coupling, that is configured for a plurality of peaks at 1,400 cm ^-1 peak to collectively represent the compression stress and tensile stress, and hydrogen gas when the flow is increased, the first peak represents the tensile stress disappears, the peaks representing the following compression stress to fall off, and thereby, a peak at 1,400 cm ^-1 no longer exists, and at 2,000 cm ^-1 indicates a tensile stress Leaving only the peak. As a result, a film having tensile stress is obtained. In some embodiments, increasing the RF power is equivalent to increasing the duration of the RF power application, and they can be used interchangeably.

A structurally important feature of TDMAT and TDEAT is not that there are bonds such as Ti-C and Ti-H on titanium, but all four hands of Ti are Ti-N bonds. Figure 2 (a) shows the chemical formula of tetrakis (dimethylamino) titanium (TDMAT). Due to this feature, the nitrogen contained in the molecular structure can be efficiently included in the film, and the carbons present in the form of dimethylamine can be easily removed by the hydrogen plasma, thereby removing the impurity carbon and forming TiN Lt; / RTI > FIG. 2 (b) is a schematic illustration showing a matrix structure of a crystalline TiN film formed using a hydrogen plasma according to an embodiment of the present invention, wherein the N-C bonds are broken and the carbons do not enter the matrix. The reduction of carbons by the hydrogen plasma makes the matrix structure of the film crystalline and the nitrogen for forming the matrix structure is provided from the precursor, not from the reactant gas. Figure 2 (c) is a schematic illustration showing a matrix structure of an amorphous TiCN film formed without the use of a hydrogen plasma, where the N-C bonds are retained and the carbons enter the matrix and interfere with the formation of a crystalline structure. On the other hand, by weakening the effect of the hydrogen plasma and using nitrogen as the reactant gas, the carbons can be present in the film, thereby leaving an impurity carbon in the film and thus forming an amorphous film constituted by TiCN.

It is also possible, in combination with the use of TDMAT and / or TDEAT, for the removal of dissociated ligands, such as Ti and dimethylamine, in the gas phase, by means of PEALD, a surface plasma treatment process in which the adsorbed material is treated on the surface of the substrate. The risk of deteriorating the film quality by forming Ti-C and Ti-H bonds due to recombination can be reduced as compared with the gas phase reaction PECVD, and the carbon can be efficiently removed without cutting Ti-N bonds in the molecular structure As shown in FIG. These are the superior features of TDMAT and TDEAT as precursors and are the reason why the deposition of various types of films is easier.

Further, as a characteristic of Ti, it can be tightly bound to oxygen, and therefore oxidation of Ti is very easy, thereby easily forming a TiO film. However, the tight bond between Ti and oxygen contributes to the removal of other elements such as carbon and nitrogen, and thus, when oxygen is used to form the TiO 2 film, carbon and nitrogen are removed by oxygen and are not present in the film. Thus, in some embodiments, when leaving oxygen and nitrogen and / or carbon simultaneously in the film, i.e., forming a TiON or TiOCN film, it uses a lamination process in which TiO films and TiN or TiCN films are alternately laminated As shown in FIG.

Generally, when the crystal of TiN is conductive and when the crystalline of TiN is improved, the sheet resistance is lowered. When carbon or oxygen is included in the film, the crystalline is deteriorated and makes its structure amorphous. In some embodiments, by controlling hydrogen gas flow and RF power, the film stress and carbon concentration can be controlled, thereby controlling the crystalline quality of the film and controlling the sheet resistance. There is no strong correlation observed between the carbon concentration and the film stress, but when the carbon concentration is extremely low and the crystalline is high, the film is characterized by compressibility. This may be because the crystallinity is improved due to the decrease of the carbon concentration, thereby making the film compressible.

In controlling membrane stress, it is extremely important to control the hydrogen supply and RF power in combination in order to obtain a membrane with tensile stress. When the hydrogen flow is too low or the RF power is too high as compared to that set to form a film with tensile stress, the film stress will change to compressive stress and therefore it is very important to control both hydrogen flow and RF power .

Since TDMAT can not be supplied simultaneously with ammonia, when ammonia is used to form a film, it is necessary to convert the gas from the precursor to ammonia after supplying the precursor. However, in some embodiments, ammonia is not used, and therefore, no conversion step is required after supplying the precursor, thereby improving the film growth rate.

During the evaluation of the TiON films, it has been found that the dry etch rate by NF ₃ and the wet etch rate by hydrogen fluoride alternate at the interface between the laminated TiO 2 and TiN layers. That is, when the laminate has a boundary between the TiO 2 layers and the TiN layers, the resistance to dry etching by NF ₃ of the laminate is higher compared to the TiO 2 or TiN monolayer and the wet etching rate due to hydrogen fluoride in the laminate The resistance is lowered. The above correlation is improved when the number of boundaries between the TiO 2 layers and the TiN layers increases. That is, when the number of boundaries is higher, the resistance to dry etching becomes higher and the resistance to wet etching becomes lower.

In some embodiments, the step coverage of the film is from about 90% to about 105%, typically about 95% or more.

The embodiments will be described with reference to the preferred embodiments. However, the present invention is not limited to the preferred embodiments thereof.

Figure 1 is a schematic diagram of a PEALD device, which may be used in some embodiments of the invention, preferably with controls programmed to perform the following sequences. In the figure, a pair of conductive flat plate electrodes 4 and 2 opposed and parallel to each other in the inside 11 of the reaction chamber 3 are provided, and HRF power (13.56 MHz or 27 MHz) 5 and 5 MHz The plasma is excited between the electrodes by applying the following LRF power (400 kHz to 500 kHz) 50 to one side and electric grounding 12 to the other side. A temperature controller is provided on the lower stage 2 (lower electrode), and the temperature of the substrate 1 placed thereon is kept constant at a given temperature. The upper electrode 4 also serves as a shower plate, and the reactive gas and the rare gas are introduced into the reaction chamber 3 through the gas flow controller 23, the pulse flow control valve 31 and the shower plate. In addition, in the reaction chamber 3, an exhaust pipe 6 is provided, through which gas in the interior 11 of the reaction chamber 3 is exhausted. In addition, the reaction chamber is provided with a seal gas flow controller 24 for introducing a seal gas into the interior 11 of the reaction chamber 3 (a separation plate for separating the reaction zone and the transfer zone within the reaction chamber It is omitted from this road).

Those skilled in the art will recognize that the apparatus includes one or more controller (s) (not shown) that are programmed or otherwise configured to cause the deposition and reactor cleaning processes described elsewhere herein to be performed. The controller (s) are in communication with the various power sources, heating systems, pumps, robotics and gas flow controllers or valves of the reactor, which will be appreciated by those skilled in the art.

Example

Examples 1 to 6

Ti containing films were deposited on substrates having patterns (aspect ratio: 2: 1) under the conditions shown in Tables 7 and 8 below using the sequence illustrated in FIG. 6 and the apparatus illustrated in FIG.

The membranes thus obtained were evaluated, and the results are shown in Table 9.

As shown in Table 9, TiN films were formed (Example 4) using a relatively high flow of hydrogen without nitrogen flow (Example 5) and a relatively high flow of hydrogen with a relatively high RF power (Example 4) . When the nitrogen flow is increased relative to the hydrogen flow, the carbon content in the film is increased, thereby forming TiCN films (Examples 1 to 3). In Examples 1 to 5, the step coverage of each film was greater than 95%, the film stress varied between -3,800 MPa and +620 MPa, and each film exhibited a high resistance to wet etching. In Example 6, a high quality TiO 2 film was formed. 4 is a transmission electron microscope (TEM) photograph of a cross-sectional view of the conformal TiCN film formed in Example 3. Fig.

Example 7-10

Ti containing films were deposited on substrates having patterns (aspect ratio: 2: 1) under the conditions shown in Table 8 and Table 10 below using the sequence illustrated in FIG. 6 and the apparatus illustrated in FIG. 1 .

The membranes thus obtained were evaluated, and the results are shown in Tables 11-13.

In Examples 7 to 9, as a trend, the carbon content was higher when the RF power was lower and when the temperature was higher. By reducing the RF power and increasing the temperature, as shown in Tables 11-13, the carbon content of the membrane was reduced and the membrane stress became compressible (Examples 7 to 9). In Examples 7 to 9, the step coverage of each film was about 100%, the film stress was varied between about -4,500 MPa and +2,000 MPa, and each film exhibited a high resistance to wet etching. In Example 10, a high quality TiO 2 film was formed, which was not significantly affected by changes in RF power and temperature.

Example 11-16

The Ti-containing films constituted by the laminates were laminated to the substrates having patterns (aspect ratio: 2: 1) under the conditions shown in Tables 14 and 15 below using the sequence illustrated in Fig. 6 and the apparatus illustrated in Fig. It was settled on.

In Example 16, each TiCN layer was formed under the same conditions as in Example 1.

The membranes thus obtained were evaluated, and the results are shown in Table 16.

As shown in Table 16, the wet and dry etch rate properties of the laminates in Examples 13-16 were not within the range between those of the two base films in Examples 11 and 12, but were different from both of them. As the number of boundaries between the TiN film and the TiO 2 film was increased, the dry etch rate was reduced, while the wet etch rate was increased (Examples 13-15).

Example 17-19

The films were formed under the same conditions as in Examples 11, 12, and 14, and the dry etch rate and wet etch rate were measured for each film. 8 is a graph showing the dry etch rates of the TiN film formed in Example 18, the TiO film formed in Example 17, and the TiON film formed in Example 19; The dry etch rate of the TiON film was significantly lower than that of the TiN film and that of the TiO film. 9 is a graph showing the wet etch rates of the TiN film formed in Example 18, the TiO film formed in Example 17, and the TiON film formed in Example 19; The wet etch rate of the TiON film was significantly higher than that of the TiN film and that of the TiO film.

Example 20

After the film forming process, the film was formed under the same conditions as in Example 6, except that the film was annealed at about 600 캜 for about 2 hours. Figure 3 shows the results of an X-ray diffraction analysis of an annealed film, indicating that the film forms anatase type crystals.

Example 21-32

Ti containing films were deposited on substrates having patterns (aspect ratio: 2: 1) under the conditions shown in Table 8 and Table 17 below using the sequence illustrated in FIG. 6 and the apparatus illustrated in FIG. 1 .

The membranes thus obtained were evaluated, and the results are shown in Table 18.

10 shows the Fourier Transform Infrared (FT-IR) spectra of the TiCN films formed in Examples 21 to 25, wherein Example 21 is a reference ("POR", process of record). The film stresses varied depending on the bonding state in the film. Generally, peaks at 2,000 cm ^-1 exhibit tensile stresses, while peaks at 1,400 cm ^-1 exhibit compressive stresses. The sum of these stresses represents the stress of the film. When the flow of hydrogen gas used as the reactant gas was reduced in Examples 21 to 23, the peak at 1,400 cm <" ¹ > was increased and the membrane became compressive. In Example 21, when the RF power was increased in Example 24, the peak at 2,000 cm <" ¹ > decreased, indicating that the crystalline quality of the film was increased and the film was very compressive.

11 shows Fourier Transform Infrared (FT-IR) spectra of TiCN films formed in Examples 26-29. When the temperature was higher in Examples 26 to 29, the peak at 2,000 cm ^-1 was higher. The peak at 2,000 cm ^-1 may be controlled by the temperature for film formation.

13 shows Fourier Transform Infrared (FT-IR) spectra of TiCN films formed in Examples 30-32. When the RF power was increased without using a hydrogen gas flow in Examples 30 to 32, the peak at 1,400 cm ^-1 became higher, the peak at 2,000 cm ^-1 became lower, and the membrane stress became very compressive .

Fig. 14 shows the results of X-ray diffraction analysis of (a) the TiCN film (carbon content: 6%) obtained in Example 21 and (b) the X of the TiCN film (carbon content: 16% Ray diffraction analysis. As shown in Fig. 14 (a), a film having a low carbon content (6%) is crystalline (Example 21), while a film having a high carbon content (16% The membrane was amorphous (Example 23). The crystals constituting the film were os- bonite TiN having a fcc (face-centered cubic) structure substantially the same as NaCl. The film contains a large number of crystals, but they have grown mainly on the (111) plane.

Figure 15 shows the results of X-ray diffraction (XRD) analysis of (a) Fourier transform infrared (FT-IR) spectra of TiCN films formed in Examples 21-23 and (b) TiCN films formed in Examples 21-23 . Like a bar in Fig. (A) and (b) in 15, when the reduction in the peak at 1,400 cm ^-1, the peak in the XRD (111) was increased, which is a peak at 1,400 cm ^-1 (111 ) ≪ / RTI > crystal plane.

Figure 16 shows the results of X-ray diffraction (XRD) analysis of (a) Fourier transform infrared (FT-IR) spectra of TiCN films formed in Examples 21 and 24 and (b) TiCN films formed in Examples 21 and 24 . Like a bar in Fig. (A) and (b) in 16, when the reduction in the peak at 2,000 cm ^-1, the peak in the XRD (200) was increased, which is a peak at 2,000 cm ^-1 (200 ) ≪ / RTI > crystal plane. In general, the FT-IR peaks (at 1,400 cm ^-1 and 2,000 cm ^-1 ) are reduced and the crystalline quality of the film is improved.

Example 33-40

Ti containing films were deposited on substrates having patterns (aspect ratio: 2: 1) under the conditions shown in Table 8 and Table 19 below using the sequence illustrated in FIG. 6 and the apparatus illustrated in FIG. 1 .

The thus obtained films were evaluated, and the results are shown in Fig. Figure 17 shows a graph showing the relationship between membrane stress and hydrogen flow in Examples 33-36 and a graph showing the relationship between membrane stress and RF power in Examples 37-40. As shown in Fig. 17, the membrane stress was controlled by the hydrogen flow, and when the hydrogen flow was increased, the membrane stress became tensile (Examples 35 and 36). Also, when the RF power was increased, the membrane stress became compressive (Example 40). By using hydrogen flow and RF power in combination with control parameters, the membrane stress can be adjusted between about -2,500 MPa and about +1,000 MPa.

Example 41-44

Ti containing films were deposited on substrates having patterns (aspect ratio: 2: 1) under the conditions shown in Table 8 and Table 20 below using the sequence illustrated in FIG. 6 and the apparatus illustrated in FIG. 1 .

The membranes thus obtained were evaluated, and the results are shown in Table 21.

In Examples 41 to 44, TDEAT was used instead of TDMAT. As shown in Table 21, the effect of RF power on the films derived from TDEAT was significantly different from that for films derived from TDMAT. When nitrogen is used (Example 41), when the RF power is lower, the carbon content is lower, while when the hydrogen is used or included (Examples 42 and 43), when the RF power is lower, Higher. When oxygen was used (Example 44), RF power did not affect the carbon content. In Examples 41 to 44, the step coverage of each film was about 100%, the film stress was changed between about -5,000 MPa and +2,000 MPa, and each film exhibited a high resistance to wet etching. In Examples 41 to 44, the film stress varied dramatically at RF power between 400 W and 600 W, indicating that the crystalline state changed as a function of RF power.

 The present invention includes other various embodiments including the above-mentioned embodiments and the following:

1) A method of forming a Ti-containing film by ALD using TDMAT or TDEAT, the method being characterized in that the film formation temperature is in the range of 50 to 250 캜 (e.g., less than 150 캜) The various films selected from TiO2, TiON, TiN, TiCN, and TiOCN films having a step coverage of 95% or more can be deposited on the substrate. In particular, the method is characterized in that the TiN film can be deposited without nitrogen-containing reactants such as ammonia and nitrogen, using the hydrogen-containing reactant and the nitrogen contained in the precursor itself. The method is also characterized in that a TiN film with tensile stress can be deposited using hydrogen as the reactant gas in combination with RF power control and sheet resistance control for the purpose of controlling the film stress.

2) The method according to 1) is characterized in that a film is formed when the TiCN film is nitrogen combined with nitrogen or hydrogen as a reactant.

3) In the process according to 1), the TiON film and the TiOCN film can be deposited by adding oxygen to the films consisting mainly of TiN and TiCN, respectively, wherein the laminate structure alternates the TiO 2 layer and the TiN or TiCN layer Is formed. Particularly, the method is characterized in that, when a TiON film is formed, a dry etching rate using NF ₃ , a wet etching rate using hydrogen fluoride, and a sheet resistance can be controlled.

4) The method according to 1) is characterized in that the TiO 2 film can be deposited using TDMAT or TDEAT as well as oxygen.

5) In the process according to 1), the reactant gas is selected from the group consisting of He, Ar, H ₂ , N ₂ , O ₂ , N ₂ O and H ₂ O to form TiO 2, TiON, TiN, TiCN, Wherein the flow rate of He is 0 to 8000 sccm, the flow rate of Ar is 0 to 8000 sccm, the flow rate of H ₂ is 0 to 5000 sccm, the flow rate of N ₂ is 0 To 500 sccm, the flow rate of O ₂ is 0 to 5000 sccm, the flow rate of N ₂ O is 0 to 5000 sccm, and the flow rate of H ₂ O is 0 to 5000 sccm.

6) In the method according to 1), the compositions of the film to be deposited can be controlled as follows: C: 0 atom% to 25 atom%; Ti: 10 atom% to 40 atom%; N: 0 atom% to 50 atom%; O: 0 atom% to 70 atom%; H: 3 atom% to 25 atom%.

7) The method according to 1) can be controlled by changing at least one of the following: the processing temperature, the flow rate of H ₂ used as the reactant gas, and the RF power.

8) In the method according to 7), the film stress can be controlled in the range of -5,000 MPa to +1,500 MPa.

9) In the method according to 7), tensile stress can be obtained under the conditions that the substrate temperature is 70 ° C. to 250 ° C., the flow rate of H ₂ is 50 sccm to 2,000 sccm, and the RF power is 150 W to 500 W .

10) The method according to 1), wherein the sheet resistance is 10? / Sq. To 5,000 OMEGA / sq. ≪ / RTI >

11) In the method according to 3), the thickness of each layer of TiO 2 and TiN or TiCN is in the range of 0.06 nm to 10 nm.

12) In the method according to 3), the ratio of the number of TiO 2 layers to the number of TiN or TiCN layers is in the range of 1: 333 to 333: 1, for example for a laminate with a thickness of 20 nm.

13) The method according to 3) is characterized in that the total oxygen concentration can be controlled by reducing or increasing the thickness of the TiO 2 layers, i.e. by increasing or decreasing the thickness of the TiN or TiCN layers relatively. The above method can also be used to control carbon and nitrogen concentrations.

14) In the method according to 3), a TiON film is formed, and its dry etching rate using NF ₃ and the wet etching rate using hydrogen fluoride can be controlled by changing the number of TiO 2 layers and TiN layers to be laminated.

15) In the method according to 14), the dry etching rate using NF ₃ can be controlled to 0.03 to 1 times that of the TiO 2 single layer, and the resistance to dry etching is improved when the number of layers constituting the laminate increases , I.e., increased.

16) In the method according to 14), the wet etch rate using hydrogen fluoride can be controlled to be 1 to 10 times that of the TiO 2 monolayer, and as the number of layers constituting the laminate increases, the resistance to wet etching decreases , I.e., decreased.

17) The method according to 1) is characterized in that the amorphous TiO 2 film can be formed not only by PEALD but also by thermal ALD due to the properties of easily oxidized Ti.

18) 1) a method of the by performing a thermal annealing at a temperature of 400 ℃ to 1,000 ℃ after forming film TiO, the anatase type TiO ₂ crystal, rutile-type TiO ₂ crystal according, or brookite-type TiO ₂ crystals Can be formed according to the annealing temperature.

19) The method according to 18) is characterized in that anatase type TiO ₂ crystals or rutile type TiO ₂ crystals exhibit photocatalytic activity, and anatase type TiO ₂ crystals exhibit superhydrophilic properties.

20) In the method according to 1), the RF power is in the range of 10 W to 2,000 W.

21) The method according to 1) is characterized in that the step coverage of the film is 95% or more.

22) The method according to 1), characterized in that the temperature of the susceptor holding the silicon substrate is in the range of 0 ° C. to 600 ° C., and the plasma generator installed in the apparatus has an arbitrary frequency between 1 MHz and 60 MHz .

 It will be understood by those skilled in the art that numerous and various modifications may be made without departing from the spirit of the invention. It is therefore to be clearly understood that the forms of the invention are illustrative only and are not intended to limit the scope of the invention.

Claims (18)

A method of forming a Ti-containing film on a substrate by plasma enhanced atomic layer deposition (PEALD) using tetrakis (dimethylamino) titanium (TDMAT) or tetrakis (diethylamino) titanium (TDEAT)
(i) introducing TDMAT and / or TDEAT into the reaction space in which the substrate is placed in a pulse;
(ii) continuously introducing an NH ₃ -containing reactant gas into the reaction space;
(iii) applying RF power in pulses to the reaction space, wherein pulses of TDMAT and / or TDEAT and pulses of RF power do not overlap; And
(iv) repeating steps (i) to (iii) to form a Ti-containing film on the substrate. The method according to claim 1,
Wherein the NH ₃ -free reactant gas is H ₂ and / or N ₂ . The method according to claim 1,
The NH ₃ reagent gas-free or containing no oxygen or not contain nitrogen, a method of forming a film containing Ti. The method according to claim 1,
Wherein the NH ₃ -containing reactant gas comprises oxygen. 3. The method of claim 2,
Wherein the NH ₃ -containing reactant gas is composed of H ₂ and a rare gas, thereby forming a Ti-containing crystalline film as the Ti-containing film in the step (iv). 3. The method of claim 2,
Wherein the Ti-containing amorphous film is formed as the Ti-containing film in the step (iv), wherein the NH ₃ -containing reactant gas is composed of H ₂ , N ₂ and a rare gas. The method according to claim 1,
Wherein the Ti-containing film has a film stress of -2,500 MPa to 800 MPa. The method according to claim 1,
the reference flow rate of H ₂ used as the reactant gas in step (ii), the reference RF power used in step (iii), and the reference deposition temperature throughout (i) to (iii) Setting a target film stress for the Ti-containing film that is greater than the film stress of the TiN crystalline film deposited by the steps (i) to (iv) under film-forming conditions; And
(ii) a step of setting the film forming temperature throughout the RF power, and (i) - (iii) steps used in the flow rate, (iii) Step of H ₂ is used as the reagent gas in the step of the H ₂ Wherein at least one of the flow rate, the RF power, and the film forming temperature is used as a control parameter for changing the film stress, and the reference flow rate of H ₂ , the reference RF power, and the reference film forming temperature are different from each other ,
And then performing steps (i) to (iv) to form the Ti-containing film. 9. The method of claim 8,
Wherein the Ti-containing film has tensile film stress. 10. The method of claim 9,
The flow rate of the H ₂ is set how smaller, a film containing Ti than the reference flow rate of the H ₂ used in the TiN crystalline film. 10. The method of claim 9,
Wherein the set RF power is less than the reference RF power used in the TiN crystalline film. 10. The method of claim 9,
Wherein the set film forming temperature is higher than the reference film forming temperature used in the TiN crystalline film. 10. The method of claim 9,
Wherein the Ti containing film contains about 4% to about 9% carbon. 10. The method of claim 9,
Wherein the Ti-containing film exhibits a peak at 2,000 cm < ^-1 > in a Fourier Transform Infrared Spectroscopy (FT-IR) graph and does not substantially exhibit peaks at 1,400 cm <" ^{1 &} gt ;. The method according to claim 1,
In the NH _3-free reaction gas is made up of a reaction gas containing a reaction gas and oxygen that does not contain oxygen, (iv) step, (i) - (iii) when the steps are repeated, NH _3-free oxygen Containing gas and NH ₃ -free oxygen containing gas are used alternately at set intervals. 16. The method of claim 15,
And it said NH _3-free oxygen-free reaction gas is hydrogen gas without nitrogen gas, the NH _3-free oxygen-containing gas is oxygen gas being as, alternately at predetermined intervals to form a film TiON made of a film-forming TiO films and TiN films , A Ti-containing film is formed. 16. The method of claim 15,
Wherein the NH ₃ -free oxygen-free reactant gas is a hydrogen gas and a nitrogen gas, and the NH ₃ -free oxygen containing gas is oxygen gas, thereby forming a TiOCN film composed of TiO 2 films and TiCN films alternately formed at a predetermined interval , A Ti-containing film is formed. The method according to claim 1,
further comprising the step of: (iv) annealing the Ti-containing film on the substrate in an atmosphere of oxygen after the step (iv) so as to form a TiO film having anatase crystal as the Ti-containing film in the step (iv) .

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